JPS6361069A - Blended type adhesive which is liquid at ordinary temperature and production thereof - Google Patents

Abstract

PURPOSE:To obtain the titled adhesive, by dispersing a powdery or granular thermoplastic adhesive which is solid at ordinary temperature in a thermoplastic which is liquid at ordinary temperature, having improved effect and capable of coating a clear coating pattern contour in small equipment under excellent economical, environmental and hygienic condition. CONSTITUTION:An adhesive, obtained by heating (A) a thermoplastic adhesive, e.g. vinyl acetate based resin, etc., which is liquid at ordinary temperature and (B) a powdery or granular thermoplastic adhesive, e.g. having 5-150mu particle diameter such as nylon 11, etc., at 90-10:10-90 blending weight ratio at a temperature of the softening point of the component (B) or below and dispersing the component (A) under condition of the viscosity lower than that of the component (B), containing the expensive powdery or granular adhesive having a relatively high melting point and high adhesive strength in a low- melting inexpensive adhesive which is liquid art ordinary temperature and capable of coating without using a spray nozzle.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mixed room temperature liquid adhesive and a method for producing the same.

[Conventional technology].

Originally, thermoplastic adhesives can be roughly divided into two types, molten and powder, based on their shape during application. In the former case, the true melt adhesive is heated and melted using a device called a hot melt applicator, and is discharged from a gun nozzle. In the case of adhesives with a high melt index, they are extruded using an extruder or the like. In the latter case, the powder is applied by spraying it together with air from a spray nozzle through an air transport pipe from a powder tank. In addition, liquid materials are generally inexpensive, but have relatively low softening and melting points, and low adhesive strength. On the other hand, powdered materials are more expensive, but have comparatively better adhesive strength and heat resistance.

Now, when applying the above-mentioned powder adhesive, it is jet-coated using a jet nozzle for powder as described above, but when this method is used, there are various problems. They are listed below.

(1) The powder coating efficiency by the injection nozzle is 40 to 70
%, which is extremely low.

(2) When applying powder, a relatively large capacity is required to suspend the powder in a tank, and equipment costs, maintenance costs, and man-hours are also relatively large. did.

(3) When heating and melting the coated powder, the powder may move and become unstable, especially if it is on a non-metallic substrate that cannot be electrostatically coated. It was difficult to dress her.

(4) The outline of the coating pattern was unclear, making it particularly difficult to coat fine lines.

(5) The extruder-type dispensing device has many drawbacks, such as its large scale, high cost, and the inability to perform a clean cut during dispensing.

[Problem to be solved by the invention]

The drawbacks of the conventional powder coating apparatus described above are unavoidable problems as long as a powder spray nozzle is used.

Therefore, the motive of the present invention was to obtain a room-temperature liquid adhesive and a method for producing the same, which can apply a powdery thermoplastic adhesive without using a spray nozzle.

[Means for solving problems]

The gist of the present invention is to mix powder-like thermoplastic adhesive, which has a relatively high melting point and adhesive strength and is expensive, into a room-temperature liquid adhesive that has a relatively low melting point and is inexpensive. Mixing is to make room temperature liquid adhesive.

Next, the mixed room temperature liquid adhesive of the present invention will be explained. The name comes from the fact that it is a mixture of an adhesive that is liquid at room temperature and a thermoplastic adhesive that is solid at room temperature and is powdery. However, since it is a new product, the name is tentative and the official name has not yet been decided.

To explain the mixing state of the mixed room temperature liquid adhesive, as shown in Fig. 1, the thermoplastic adhesive P with a relatively high melting point is in a solid powder-like state, and the thermoplastic adhesive P with a relatively high melting point is in the form of a solid powder and granule, and the thermoplastic adhesive P with a lower melting point, that is, a room temperature liquid is mixed. The adhesive is uniformly dispersed in the adhesive H.

There are various thermoplastic adhesives in powder form that can be used in these applications, but the one used in the experiments of the present invention is nylon 11 (melting point: 186°C). In addition, room-temperature liquid adhesives that serve as bases or binders include the most common and inexpensive thermoplastic vinyl acetate resin, and room-temperature liquid reactive adhesives include ultraviolet curing types and moisture absorption curing types. , thermosetting type, multi-liquid reaction curing type, etc.

The weight mixing ratio of the thermoplastic adhesive in the form of powder and the room temperature liquid adhesive serving as the base or binder is 10 to 90 to 29.
Chill within the range of 0 to 10%.

That is, as shown in FIG. 1, a thermoplastic adhesive (such as nylon 11) is uniformly dispersed in the form of powder or granules in a room-temperature liquid adhesive, or the powder is a room-temperature liquid adhesive. (Figure 2).

The above-mentioned mixed type room temperature liquid adhesive may be produced by a general stirring and mixing method. That is, using a stirring mixing tank, place a room-temperature liquid adhesive to serve as a base or binder, and add a powdered thermoplastic adhesive therein, or vice versa, at a weight ratio of 90 to 10%:
Add and stir to uniformly disperse within the range of 10 to 90%. In this case, it is desirable that the thermoplastic adhesive in the form of powder or granules is previously subjected to a surface treatment using plasma or corona discharge or the like. The reason is to improve dispersion. Further, in the case of a thermoplastic room temperature liquid adhesive, it may be slightly heated to lower its viscosity and increase work efficiency.

Furthermore, the heating temperature must be lower than the softening point of the powdered thermoplastic adhesive to be mixed therein.

In addition, at least one of the above-mentioned room-temperature liquid adhesive or powder-like thermoplastic adhesive generally contains pigments and/or extenders, dispersion stabilizers, surfactants, etc. as additives. There are many cases where

[For production]

The effect of adhesion using the mixed room-temperature liquid adhesive according to the present invention will be explained.

Mixed room temperature liquid adhesives, including thermoplastic and thermosetting adhesives, are generally applied onto the surface of the object from a gun nozzle via a liquid pump. The condition of the applied material at this time is the first
As shown in the figure, the solid powder-like thermoplastic adhesive P is uniformly dispersed and suspended in the liquid of the room temperature liquid adhesive H, and the temperature of the room temperature liquid adhesive is If the amount is smaller than the amount of thermoplastic adhesive in the form of powder or granules, the room-temperature liquid adhesive becomes a binder and binds the powder or granules together, as shown in Figure 2. ing.

After the mixed room-temperature liquid adhesive as described above is applied onto the surface of the object to be coated, it is first heated non-contactly (such as by far infrared rays) or contactly (such as by using a heated press plate). The temperature is set to be higher than the melting point of the powdered thermoplastic adhesive. Then,
Among the mixed room temperature liquid adhesives, thermoplastic room temperature liquid adhesives have a lower viscosity, and thermoplastic ones begin to harden. Furthermore, the thermoplastic adhesive in the form of powder or granules also melts when it reaches its melting point. Then, they are adhesively bonded to each other and adhered to one surface of the object to be ejected, as shown in FIG. On the other hand, the curing speed of the thermosetting adhesives mentioned above is generally slower than the melting rate of thermoplastic adhesives. Therefore, the thermoplastic adhesive completely melts and adheres to the surface of the workpiece before its thermal curing is completed.

Furthermore, the order of adhesion of the above-mentioned mixed room-temperature liquid adhesive is slightly different between one-sided adhesive and double-sided adhesive. In the case of single-sided adhesion, a mixed room-temperature liquid adhesive can be applied onto the surface of the object to be coated through a gun nozzle using a liquid pressure pump, and then heated in a non-contact or contact manner (see Figure 3). ). The temperature of the adhesive needs to be higher than the melting point of the powdered thermoplastic adhesive.

Moreover, if necessary, pressurization or heating and pressurization may be performed simultaneously thereafter.

On the other hand, in the case of double-sided adhesion, the adhesive is first applied in the same way as in the case of single-sided adhesion, but immediately after that, the object to be adhered is placed on top of it. Then, heat or pressurize at the same time (Figure 6)
. That is, in addition to the one-sided adhesion process described above, there is one step of overlapping the objects to be adhered.

Note that the room-temperature liquid adhesive that is the composition of the mixed room-temperature liquid adhesive of the present invention generally contains volatile components such as solvents, so immediately after dispensing and dispensing, after these are blown off by heating, etc. Furthermore, it is desirable to melt the powdery thermoplastic adhesive by heating it to a higher temperature.

Example 1 The above-mentioned application method is a method in which a hot-melt applicator is used to eject the material through a gun nozzle, but it is also possible to perform ejection application (spraying). In this case, unlike in the case of the conventional powder spray described above, the coating effect can be improved without the powder scattering. Further, this mixed hot melt adhesive has greater thixotrophic ink properties than general hot melt adhesives, and has the additional advantage of being able to obtain a smooth spray pattern.

Instead of using the above-mentioned hot melt applicator, the 2° mixed hot melt adhesive can also be discharged using an extruder.

(However, as mentioned above, a general hot-melt applicator is sufficient, and it is actually simpler and easier to use.) Above, we have explained this adhesive-saving cloth, but the application method is exactly the same. It can be constructed in

〔Effect of the invention〕

When applying thermoplastic adhesives in the form of powder or granules, the use of the mixed hot melt adhesive of the present invention eliminates problems such as low application efficiency and unclear outlines of application patterns caused by conventional jet nozzle methods. The coating efficiency of the granular thermoplastic adhesive is 100%, and the coating pattern outline is
In particular, in the case of thermosetting hot melts, pressurized work can be performed more clearly and with smaller equipment, contributing to improvements in economic efficiency and environmental hygiene.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a mixed state of a room-temperature liquid adhesive based on the composition of a mixed-type room-temperature liquid adhesive according to the present invention (hereinafter the same names will be omitted due to the present invention).
The figure is an explanatory diagram of the mixing state of a room-temperature liquid adhesive with the same composition as the binder. Figure 3 is an explanation of the heating state of a mixed hot-melt adhesive using non-contact far-infrared heating for one-sided adhesion of the coated material. Figure 4 is the same as above figure A″
Figure 5 is an enlarged view of the state after heating of the above part. Figure 5 is an explanatory diagram of the state of heating and pressing by the heating pressure plate on the coated material in single-sided bonding. Figure 6 is an explanatory diagram of the bonding work order in double-sided bonding.
The figure is an explanatory diagram of heating and pressurizing operation in the same as above. Figure 8 is the same as above.
Enlarged view of part B'' Explanation of main symbols 1.11i3...Subject to be adhered 2.12...
... Sprayed object (mixed hot melt adhesive)
H: Hon 1-melt adhesive P: Thermoplastic adhesive

Claims (1)

[Claims] 1. A mixed room-temperature liquid characterized by dispersing a powdery thermoplastic adhesive P that is solid at room temperature in a thermoplastic room-temperature liquid adhesive H. glue. 2. Heat the thermoplastic room-temperature liquid adhesive at a certain temperature below the softening point of the powdered thermoplastic adhesive to be mixed into it to form a lower viscosity state of the room-temperature liquid adhesive. A method for producing a mixed room-temperature liquid adhesive, characterized in that the above-mentioned solid thermoplastic adhesive in the form of powder or granules is introduced into the mixture, and the solid thermoplastic adhesive is stirred to uniformly disperse the adhesive. 3. The particle size of the thermoplastic adhesive powder is 5 to 150μ
Claims 1 and 2 are characterized in that:
Mixed room-temperature liquid adhesive and its manufacturing method. 4. The mixed liquid adhesive and the method for producing the same according to claims 1 and 2, wherein the powdery thermoplastic adhesive has a melt index of 1 to 100. 5. The mixed room-temperature liquid adhesive of item 1 and item 2, characterized in that the difference in softening point or melting point between the room-temperature liquid adhesive and the powdered thermoplastic adhesive is 15°C or more. Adhesives and their manufacturing methods. 6. Claims 1 and 2, characterized in that the weight mixing ratio of the room-temperature liquid adhesive and the powdered thermoplastic adhesive is 90-10%:10-90%. Mixed room temperature liquid adhesive and its manufacturing method. 7. Additives such as pigments and/or fillers, dispersion stabilizers, surfactants, etc. are mixed into at least one side of the hot melt adhesive or powdery thermoplastic adhesive. A mixed room-temperature liquid adhesive and a manufacturing method thereof according to claims 1 and 2. 8. The thermoplastic room temperature liquid adhesive is a room temperature liquid reactive adhesive.